1. Field of the Invention
The invention relates to new salts of pyromellitic acid, to a process for their preparation and to their use for the production of matt epoxide and hybrid powder coatings.
2. Discussion of the Background
Pyromellitic acid is conventionally used in matt epoxide and hybrid powder coatings. For example, U.S. Pat. No. 3,947,384 and U.S. Pat. No. 4,007,299 describe processes for the production of matt coatings, in which epoxy resins are cured using salts of pyromellitic acid and cyclic amidines (imidazolines, tetrahydropyrimidines). Unfortunately, such resin requires temperatures of 180.degree. C. to 200.degree. C. for curing.
Curing agents having the advantageous properties of the pyromellitic acid salts of U.S. Pat. No. 3,947,384 and U.S. Pat. No. 4,007,299 and which can be cured at about 20.degree. C. or lower, which is not currently possible, are desirable.